Проблема со стилем всплывающей подсказки ползунка UWP

Моя всплывающая подсказка сначала выглядит нормально, а через пару секунд имеет белую рамку. Изображение имеет прозрачный фон. Просто интересно, как избавиться от этого?

Определение класса:

using System;
using Windows.UI.Xaml;

using SynaAudio.Core;

namespace TestProject.Client.MixerPage
{
    /// <summary>
    /// Interaction logic for MasterSettingsHandler.xaml
    /// </summary>
    public partial class MasterSettingsHandler
    {
        public MasterSettingsHandler()
        {
            try
            {
                InitializeComponent();
            }
            catch (Exception e)
            {
            }
        }
    }
}

xaml-код:

<Page x:Class = "TestProject.Client.MixerPage.MasterSettingsHandler"
      xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x = "http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc = "http://schemas.openxmlformats.org/markup-compatibility/2006" 
      xmlns:d = "http://schemas.microsoft.com/expression/blend/2008" 
      mc:Ignorable = "d" Width = "660" Height = "50" >

    <Page.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source = "ms-appx:///TestProject/Resources/Templates/Slider.xaml"/>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Page.Resources>

    <Border Name = "bdrMas" Background = "#FF262626">
        <Grid Name = "gridMas" Margin = "10,0,10,0" VerticalAlignment = "Stretch">

            <Grid.ColumnDefinitions>
                <ColumnDefinition Width = "150" />
                <ColumnDefinition Width = "40" />
                <ColumnDefinition Width = "*" />
                <ColumnDefinition Width = "120" />
            </Grid.ColumnDefinitions>

            <TextBlock Name = "_endPointLabel" 
                       Text = "Master Volume" 
                       FontSize = "13" Margin = "10,0"
                       HorizontalAlignment = "Left" VerticalAlignment = "Center" Foreground = "#FFDADADA"
                       TextAlignment = "Center" TextTrimming = "WordEllipsis" TextWrapping = "Wrap" />

            <Slider Name = "_volumeSlider" x:FieldModifier = "public"
                    Style = "{StaticResource SaSlider}"
                    Value = "{Binding Path=Volume, Mode=TwoWay}" 
                    HorizontalAlignment = "Stretch" VerticalAlignment = "Center"
                    Grid.Column = "2" 
                    LargeChange = "1" SmallChange = "1" 
                    Orientation = "Horizontal" />
        </Grid>
    </Border>

</Page>

Стиль слайдера:

<ResourceDictionary xmlns = "http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x = "http://schemas.microsoft.com/winfx/2006/xaml" >

    <Style x:Key = "SaSlider" TargetType = "Slider" >
        <Setter Property = "Template" Value = "{StaticResource FancySliderControlTemplate}" />
    </Style>

    <ControlTemplate x:Key = "FancySliderControlTemplate" TargetType = "Slider">
        <Grid x:Name = "RootGrid" Margin = "{TemplateBinding Padding}">
            <Grid.Resources>
                <Style TargetType = "Thumb" x:Key = "SliderThumbStyle">
                    <Setter Property = "BorderThickness" Value = "0" />
                    <Setter Property = "Background" Value = "#FF36A4F1" />
                    <Setter Property = "Template">
                        <Setter.Value>
                            <ControlTemplate TargetType = "Thumb">
                                <Border x:Name = "bdrThumb" Background = "{TemplateBinding Background}"
                                        BorderBrush = "{TemplateBinding BorderBrush}"
                                        BorderThickness = "0"
                                        CornerRadius = "7" />
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </Grid.Resources>
            <Grid.RowDefinitions>
                <RowDefinition Height = "Auto" />
                <RowDefinition Height = "*" />
            </Grid.RowDefinitions>
            <VisualStateManager.VisualStateGroups>
                <VisualStateGroup x:Name = "CommonStates">
                    <VisualState x:Name = "Normal" />
                    <VisualState x:Name = "Pressed">
                        <Storyboard>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalTrackRect" Storyboard.TargetProperty = "Opacity">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "0.9" />
                            </ObjectAnimationUsingKeyFrames>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalThumb" Storyboard.TargetProperty = "Opacity">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "0.9" />
                            </ObjectAnimationUsingKeyFrames>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalDecreaseRect" Storyboard.TargetProperty = "Opacity">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "0.9" />
                            </ObjectAnimationUsingKeyFrames>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalThumb" Storyboard.TargetProperty = "Height">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "16" />
                            </ObjectAnimationUsingKeyFrames>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalThumb" Storyboard.TargetProperty = "Width">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "16" />
                            </ObjectAnimationUsingKeyFrames>
                        </Storyboard>
                    </VisualState>
                    <VisualState x:Name = "Disabled">
                    </VisualState>
                    <VisualState x:Name = "PointerOver">
                        <Storyboard>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalTrackRect" Storyboard.TargetProperty = "Opacity">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "0.8" />
                            </ObjectAnimationUsingKeyFrames>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalThumb" Storyboard.TargetProperty = "Opacity">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "0.8" />
                            </ObjectAnimationUsingKeyFrames>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "SliderContainer" Storyboard.TargetProperty = "Opacity">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "0.8" />
                            </ObjectAnimationUsingKeyFrames>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalDecreaseRect" Storyboard.TargetProperty = "Opacity">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "0.8" />
                            </ObjectAnimationUsingKeyFrames>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalThumb" Storyboard.TargetProperty = "Height">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "16" />
                            </ObjectAnimationUsingKeyFrames>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalThumb" Storyboard.TargetProperty = "Width">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "16" />
                            </ObjectAnimationUsingKeyFrames>
                        </Storyboard>
                    </VisualState>
                </VisualStateGroup>
                <VisualStateGroup x:Name = "FocusEngagementStates">
                    <VisualState x:Name = "FocusDisengaged" />
                    <VisualState x:Name = "FocusEngagedHorizontal">
                        <Storyboard>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "SliderContainer" Storyboard.TargetProperty = "(Control.IsTemplateFocusTarget)">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "False" />
                            </ObjectAnimationUsingKeyFrames>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetName = "HorizontalThumb" Storyboard.TargetProperty = "(Control.IsTemplateFocusTarget)">
                                <DiscreteObjectKeyFrame KeyTime = "0" Value = "True" />
                            </ObjectAnimationUsingKeyFrames>
                        </Storyboard>
                    </VisualState>
                </VisualStateGroup>
            </VisualStateManager.VisualStateGroups>
            <ContentPresenter x:Name = "HeaderContentPresenter"
                              x:DeferLoadStrategy = "Lazy"
                              Visibility = "Collapsed"
                              Foreground = "{ThemeResource SliderHeaderForeground}"
                              Margin = "{ThemeResource SliderHeaderThemeMargin}"
                              Content = "{TemplateBinding Header}"
                              ContentTemplate = "{TemplateBinding HeaderTemplate}"
                              FontWeight = "{ThemeResource SliderHeaderThemeFontWeight}"
                              TextWrapping = "Wrap" />
            <Grid x:Name = "SliderContainer"
                    Background = "{ThemeResource SliderContainerBackground}"
                    Grid.Row = "1"
                    Control.IsTemplateFocusTarget = "True">

                <Grid x:Name = "HorizontalTemplate" >
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width = "Auto" />
                        <ColumnDefinition Width = "Auto" />
                        <ColumnDefinition Width = "*" />
                    </Grid.ColumnDefinitions>
                    <Grid.RowDefinitions>
                        <RowDefinition Height = "6" />
                        <RowDefinition Height = "Auto" />
                        <RowDefinition Height = "6" />
                    </Grid.RowDefinitions>
                    <Rectangle x:Name = "HorizontalTrackRect"
                               Fill = "#FF3D3D3D"
                               Height = "5"
                               Grid.Row = "1"
                               Grid.ColumnSpan = "3" />

                    <Rectangle x:Name = "HorizontalDecreaseRect" Grid.Row = "1" Grid.Column = "2" >
                        <Rectangle.Fill>
                            <LinearGradientBrush StartPoint = "0,0" EndPoint = "1,1">
                                <GradientStop Color = "#FF16486C" Offset = "0.0" />
                                <GradientStop Color = "#FF36A4F1" Offset = "1.0" />
                            </LinearGradientBrush>
                        </Rectangle.Fill>
                    </Rectangle>

                    <TickBar x:Name = "TopTickBar"
                             Visibility = "Collapsed"
                             Fill = "{ThemeResource SliderTickBarFill}"
                             Height = "{ThemeResource SliderOutsideTickBarThemeHeight}"
                             VerticalAlignment = "Bottom"
                             Margin = "0,0,0,4"
                             Grid.ColumnSpan = "3" />
                    <TickBar x:Name = "HorizontalInlineTickBar"
                             Visibility = "Collapsed"
                             Fill = "{ThemeResource SliderInlineTickBarFill}"
                             Height = "{ThemeResource SliderTrackThemeHeight}"
                             Grid.Row = "1"
                             Grid.ColumnSpan = "3" />
                    <TickBar x:Name = "BottomTickBar"
                             Visibility = "Collapsed"
                             Fill = "{ThemeResource SliderTickBarFill}"
                             Height = "{ThemeResource SliderOutsideTickBarThemeHeight}"
                             VerticalAlignment = "Top"
                             Margin = "0,4,0,0"
                             Grid.Row = "2"
                             Grid.ColumnSpan = "3" />
                    <Thumb x:Name = "HorizontalThumb"
                           Style = "{StaticResource SliderThumbStyle}"
                           DataContext = "{TemplateBinding Value}"
                           Height = "14"
                           Width = "14"
                           Grid.Row = "0"
                           Grid.RowSpan = "3"
                           Grid.Column = "1"
                           AutomationProperties.AccessibilityView = "Raw" >
                        <ToolTipService.ToolTip>
                            <ToolTip>
                                <ToolTip.Style>
                                    <Style TargetType = "ToolTip">
                                        <Setter Property = "Template">
                                            <Setter.Value>
                                                <ControlTemplate TargetType = "ToolTip">
                                                    <ContentPresenter
                                                            x:Name = "LayoutRoot"
                                                            Foreground = "White"
                                                            Background = "Transparent"
                                                            Content = "{TemplateBinding Content}"
                                                            ContentTemplate = "{TemplateBinding ContentTemplate}">
                                                        <VisualStateManager.VisualStateGroups>
                                                            <VisualStateGroup x:Name = "OpenStates">
                                                                <VisualState x:Name = "Closed">
                                                                    <Storyboard>
                                                                        <FadeOutThemeAnimation TargetName = "LayoutRoot" />
                                                                    </Storyboard>
                                                                </VisualState>
                                                                <VisualState x:Name = "Opened">
                                                                    <Storyboard>
                                                                        <FadeInThemeAnimation TargetName = "LayoutRoot" />
                                                                    </Storyboard>
                                                                </VisualState>
                                                            </VisualStateGroup>
                                                        </VisualStateManager.VisualStateGroups>
                                                    </ContentPresenter>
                                                </ControlTemplate>
                                            </Setter.Value>
                                        </Setter>
                                    </Style>
                                </ToolTip.Style>
                                <Grid Background = "Transparent">
                                    <Image Source = "ms-appx:///SmartAudioSkinHP2020/Resources/Images/Misc/Tooltip.png" Stretch = "Fill" />
                                    <TextBlock Text = "{TemplateBinding Value}" Foreground = "White" HorizontalAlignment = "Center" VerticalAlignment = "Center" />
                                </Grid>
                            </ToolTip>
                        </ToolTipService.ToolTip>
                    </Thumb>
                </Grid>
            </Grid>
        </Grid>
    </ControlTemplate>
</ResourceDictionary>

Целевая версия: Windows 10 1803 17134

Похоже, что обычная всплывающая подсказка для большого пальца отображается через несколько секунд после моей. Я предполагаю, что это должно быть исправлено в стиле слайдера.

Работал бы над другими задачами, если бы это был WPF :(